promethean PRM-20, Service Manual

Page: 32 / 120

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electrical Adjustments
5. Connect an oscilloscope to test point “
tP_r1
” (+)
and chassis ground (-).
6. Select item no. “
1
” and change data value to adjust
the pedestal level and black level to be the same lev-
el.
7. Connect an oscilloscope to test point “
tP_B1
” (+)
and chassis ground (-).
8. Select item no. “
2
” and change data value to adjust
the pedestal level and black level to be the same lev-
el.
P
edestal Lebel
Blac
k Lebel
1. Enter the service mode.
. Receive the 16-step grey scale composite video sig-
nal with
Video [Video]
mode.
. To start the auto-calibration for Component adjust-
ment, select group no. “
260
”, item no. “
0
” and then
change data value from “
0
” to “
1
”. After the auto-cali-
bration completed, "OK" will appear on the screen.
5. Auto Calibration adjustment [Video]
Gain adjustment [Video]
1. Enter the service mode.
. Receive the 16-step grey scale composite video signal
with
Video [Video]
mode.
. Connect an oscilloscope to test point “
tP_G1
” (+)
and chassis ground (-).
4. Select group no. “
20
”, item no. “
0
” and adjust the
amplitude “
a
” to be minimum by changing the Data
value.
(a)
White Level
1. Enter the service mode.
. Receive the 50%-Whole Gray computer signal with
computer1 [rGB] mode.
. Select group no. “
100
”, item no. “
92
” and change
data value to “
2
” to reduce the panel frequency.
4. Project only green light component to the screen.
5. Select group no. “
101
”, item no. “
1
” and change
data value to obtain the minimum flicker on the
screen.
6. Project only red light component to the screen.
7. Select item no. “
0
” and change data value to obtain
the minimum flicker on the screen.
8. Project only blue light component to the screen.
9. Select item no. “
2
and change data value to obtain
the minimum flicker on the screen.
10. Select group no. “
100
”, item no. “
92
” and change
data value to “
0
” to reset the panel frequency.
6. Common Center adjustment
below adjustment is performed when the above auto
calibration is failed.
Gain adjustment [component]
1. Enter the service mode.
. Receive the 16-step grey scale computer signal with
computer1 [rGB]
mode.
. Connect an oscilloscope to test point “
tP_G1
” (+)
and chassis ground (-).
4. Select group no. “
0
”, item no. “
3
” and adjust the ampli-
tude “
a
” to be minimum by changing the Data value.
5. Connect an oscilloscope to test point “
tP_r1
” (+)
and chassis ground (-).
6. Select group no. “
0
”, item no. “
4
” and adjust the ampli-
tude “
a
” to be minimum by changing the Data value.
7. Connect an oscilloscope to test point “
tP_B1
” (+) and
chassis ground (-).
8. Select group no. “
0
”, item no. “
5
” and adjust the ampli-
tude “
a
” to be minimum by changing the Data value.
(a)
White Level